16 AGRICULTURAL ANALYSIS 



contain twelve per cent, of phosphoric acid, when in reality it con- 

 tained only eight per cent, in the moist state. 



17. Barn- Yard Manures. The sampling of stall and barn-yard 

 manures is more difficult on account of the fact that the materials 

 are not homogeneous and that they are usually mixed with straw 

 and other debris from the feed trough, and only the greatest care 

 and patience will enable the operator to secure a fair sample. 



In the case of liquid manures the liquid should be thoroughly 

 stirred before the sample is taken. In a given case the difficulty 

 of securing representative samples of stall manure is described 

 and also methods of removing it. 6 The stall manure sampled had 

 been piled in the cattle-yard for a time and the cattle were al- 

 lowed to run over the heaps for an hour or two each day. Pigs 

 .were allowed free access to the heaps in order to insure a more 

 perfect mixture of the ingredients. 



Twenty-nine loads of 3000 pounds each were sampled from the 

 exposed heap and 34 loads of 2000 pounds each were sampled 

 from the covered heap. From each load were removed 

 two carefully selected portions of 10 pounds each, which 

 were placed in separate covered boxes numbered A and B. When 

 the sampling was completed these boxes were covered. After 

 being removed to the laboratory the boxes were weighed and the 

 contents thoroughly mixed. Two samples of 12 liters each 

 were drawn from each box. One-third of this was chopped in 

 a large meat chopper and the other two-thirds taken into the 

 laboratory without being cut. These samples, on entering the 

 laboratory, were weighed and dried at a temperature of 60 to 

 secure the samples for analysis. 



18. Sampling of Materials Used for Road Building. The mate- 

 rials of which roads are built, especially the rock materials, have 

 of late years been subjected to careful scientific examination. 

 The methods may be applied also to minerals containing fertilizer 

 ingredients. In the examination of rocks and rock materials 

 which are used to build roads, the sample which is sent should 

 be large enough to give assurance that it practically represents 

 the materials employed. For this purpose not less than 30 pounds 



5 Proceedings iath and i3th Meetings of the Society for the Promotion 

 of Agricultural Science, 1891-2 : 139. 



